Electric signal recorders



June 23, 1964 A. G. COOLEY ELECTRIC SIGNAL RECORDERS 2 Sheets-Sheet 1 Filed May 16, 1961 Facsl'mf/e signals Source 0f Cammufazor INVENTOR. AUSTIN G- COOLEY ATTORNEY A. G. COOLEY ELECTRIC SIGNAL RECORDERS 2 Sheets-Sheet 2 FIG.5

FIG.6

FIG. 7

INVENTOR. AUSTIN c. COOLEY W i K 4 ATTORNEY June 23, 1964 Filed May 16. 1961 United States Patent 3,133,429 ELEiITRIC IGNAL RECQRDERS Austin G. Cooley, New York, N.Y., assignor to Litton Systems, incorporated, Beverly Hills, Calif. Filed May 16, 1961, Ser. No. 118,755 17 Claims. (Cl. 346- 161) This invention relates to electric signal recorders and more particularly to facsimile recorders of the mechanical or pressure-marking types.

The object of the invention, in general terms, is to 1ncrease the speed and improve the definition or fidelity of facsimile recorders of this class;

A further object of the invention is to provide a highspeed signal recorder which will operate for an extended period of time without maintenance or adjustment.

Another object of the invention is to improve the construction of amechanical recording unit by a novel arrangement for accurately controlling the position and recording pressure of an element employed to mark a pressure-sensitive recording surface. This marking element is preferably of the free-floating blade type disclosed in my prior application for US. Letters Patent, Ser. No. 839,959, filed September 14, 1959, but modified in accordance with the present invention There is disclosed in said copending application a facsimile recorder of the kind employing a rotatable platen or drum pro vided with a helical rib or anvil and a marking blade which is actuated by an electro-magnet and which is mounted independently of any pivotal supports, springs or damping elements.

This construction has been utilized in practice for making excellent copies at normal speeds under the control of a standard facsimile transmitter, with minimal adjustment or maintenance. However, it will be apparent that the weight or mass of the marking blade is a limiting factor in attaining optimum recording at high speed, and this is particularly true of the larger units where the blade may be fifteen to twenty inches or more in length as used for recording maps, charts or the like. In a recorder as de scribed in said prior application, it is essential that the blades have sufiicient longitudinal stiifness or rigidity so that it can be actuated along its entire length toward and away from its marking position; thus, as the length of the blade increases, to maintain uniform recording the mass per unit length usually must be increased where the entire blade is actuated by the drive magnet. Obviously this limits the speed of response of the recording unit below that which is necessary for higher speeds of.

recording.

In accordance with the invention, this difficulty is overcome by employing a marking element or blade having a certain amount of transversed flexibility, and by providing a segmented or multi-polar electromagnet assembly arranged to apply maximum recording force to said marking element at the point of intersection with the helix rib, thus marking the recording blank without causing bodily movement of the entire length of the marking blade. The electromagnet assembly may be provided with a series of energizing coils which are energized successively by the signal currents through a commutator, rotary inductive distributor or the like, thereby concentrating the driving power at the area to be recorded.

These and other objects and advantages of the invention will become apparent from the following description of the embodiments thereof shown 011 the accompanying drawings, in which a FIG. 1 is a partial perspective view-of a facsimile recorder embodying the invention; 7

FIG. 2 is a plan view of the recording unit and helix drum shown in FIG. 1;

FIGS. 3and 4 are detailed views to an enlarged scale of 3,138,429. Patented June 23, 1964 the electromagnetic recording unit shown in FIGS. 1 and 2;

FIG. 5 is a diagrammatic view showing the arrange ment of the coils or windings of the electromagnet assembly;

FIG. 6 is a schematic drawing of the windings and commutator; and

FIG. 7 is a modification employing a rotary inductive distributor in place of the commutator.

Referring to FIGS. 1' and 2, these figures illustrate the invention as embodied in the recording assembly of a facsimile recorder. For the sake of simplicity, the drive and synchronizing. elements of the recorder, being conventional, are not shown. The recorder illustrated by way of example is of the flat or continuous-web type, utilizing a web of recording material 10, for example, having its surface coated with a pressure-responsive coating. Recording blanks of this type are well known in the art. When subjected to pressure in localized areas, the coating at those areas is discolored or becomes transparent, to expose the contrasting color of a backing, thus producing the desired recorded information invisible form. A number of such materials are in general use, similar to that disclosed in the US. patent to H. R. Dalton, No. 2,313,810.

It will be understood that, in place of a single sheet or web, two or more sheets may be employed where multiple copies are desired. Also carbon transfer paper with a sheet of ordinary paper may be usedin place of the pressure-responsive coated blank, and such alternative arrangements being common in every day practice this requires no illustration. Merely for the sake of simplicity, the sheet or recording blank 10 is shown as a single sheet of pressure-responsive paper.

The recording blank or web 10 is fed upwards from a suitable supply roll sothat it moves past and in engagement with a helical rib 11 on a rotatable cylinder 12, which may be in the form of a drum or other platen support for the Web or sheet 10. The cylinder 12 is attached to a suitable driving shaft 13, which is rotated in the direction of the arrow. The feeding of the blank 10 and rotation of the cylinder 12 are synchronized in accordance with the usual practice with the scanning of the subject copy in the transmitter. The point of intersection of the rib 11 with a marking blade or member 15 provides a pressure point or localized marking area which moves across the width of the recording blank as well understood in the facsimile recording art. Thus, the helix rib 11 constitutes a movable support or anvil behind the blank 10 and the recording member 15 exerts variable pressure engagement against the surface of the blank. The marking member 15 may be in the form of an armature for the electromagnetic recording unit, as shown in my prior application referred to above, or may be a separate marking blade which is attached to an armature of an electromagnet assembly as shown generally in the prior application for Letters Patent of H. S. Stein et al., Ser. No. 861,529, filed December 23, 1959. The electromagnet assembly 20 shown is responsive to applied electrical signals and controls the amount of pressure exerted by the forward longitudinal edge 16 of the elongated marking element 15 on the blank 1%. As shown and described herein, the present invention in preferably embodied in a recording system employing a freefioating marker element mounted independently of any pivotal supports, springs or damping elements, as disclosed and claimed in said prior Cooley and Stein et al. applications but is not limited to this mounting construc- In accordance with the invention, the electromagnet assembly as is arrangedto cause the marking element 15 to exert maximum pressure on the recording blank at the recording area, namely opposite the point of intersection with the helix rib 11. With such an arrangement, the helix 11 as shown instead of being a single turn helix, may consist of two or more turns and still provide only .1 single marking point at any particular instant on the recording blank.

In the preferred embodiment of the invention, as illustrated more clearly in FIGS. 3 and 4, the marking element 15 is in the form of a thin fiat blade having a rectilinear marking edge 16 and attached at its rear edge to a separate magnetic armature 17. In order to impart a predetermined transverse flexibility to the marking element 15, this element and the armature 17 are provided with a series of transverse partial slots 18 and 19. The armature 17 may consist of a series of segments or tongues instead of a continuous slotted strip, if desired. The flexibility imparted to the marking element 15 by this construction permits marking pressure on the recording blank at a localized area by distorting the edge of the marking element as will be described.

The electromagnetic assembly 20 consists of a soft iron core member 21 extending substantially the length of the recording assembly, a plurality of individual iron core members having salient poles 22 adjacent the edge of the core member 21, and a supporting member 23, to which core members 21 and 22 are attached. The armature 17, or series of armatures, is provided with an off-set portion 17a in the gap formed between the ends' of the core members 21 and 22, as shown in FIG. 4. Thus when the core members are magnetized, the armature 17 is attracted in a direction to actuate the marking element 15 and exert pressure on the recording blank 10. It will be apparent that by this construction, the salient poles 22 are arranged in an array in line with the edge of the recording unit and, by progressively energizing one or more poles 22, a localized pressure may be exerted at a given point on the armature 17 and attached marking element 15. The friction between the armature 17 and core member 21 may be reduced by the use of a lubricant or a coating such as Teflon on the rubbing surfaces.

In order to obtain such progressive energization of the poles of the magnet 20, a series of coils or windings 25 are providedon the pole pieces 22. The windings 25 are insulated from each other and from the core, as for example by insulating strips 26 and 27. The coils 25 are arranged to produce a progressive or travelling-wave energization of the array of pole pieces 22 which is synchronized with the rotation of the helix rib 11. Thus as shown in FIG. 5, each of the coils 25 may surround three separate and adjacent pole pieces. In order to obtain a symmetrical arrangement providing uniform energization of the pole pieces 22, one coil 25a surrounds two pole pieces at one end and is connected in series with a coil 25b surrounding the pole piece 22 at the opposite end of the array. Similarly, a coil 25c surrounding a single end pole piece is connected in series with a coil 25d surrounding two pole pieces 22 at the oppositeend of the array.

In accordance with the invention, the pole pieces 22 are progressively energized singly, or in groups, by connecting the individual windings 25 to the signal current source in a manner to provide localized progressive forces on the marking element 15. Thus as shown in FIG. 6, by way of example, the windings 25 are each connected to a series of commutator segments 30, shown in developed form, except for the pairs of windings 25a, 25b and 25c,

2501, each of said pairs being connected to a single commutator segment 30. A rotating brush assembly consisting of spaced brushes 31 and 32 is connected through adjacent brushes 33 and 34 respectively to the stationary slip rings 35 to which the source of signal currents is connected. In this manner it will be apparent that the windings 25, which at any instant are connected to the segments 30 between the brushes 31 and 32, are energized by the signal currents. In order to prevent back currents through the disconnected windings, two rectifiers 28 and 29 are connected between the 5th and 13th commutator segments and associated coils 25 as shown. With this arrangement, when signal current is applied to the slip rings 35, the connected group of windings 25 will be energized in accordance with the strength of the signal current, and, since the operative group of windings progressively changes, the marking element 15 is actuated at a localized area. By reason of its flexibility, element 15 exerts marking pressure on the recording blank 19 without requiring bodily movement of the marking element 15 as a whole. This results in substantially increased speed of recording and improved fidelity. The rotation of the brushes 31-34 is synchronized with the rotation of the cylinder 12 and helix 11, as by connection to the shaft 13.

Instead of employing a synchronous commutator, a rotary inductive type distributor, as shown in FIG. 7, may be employed to progressively energize the windings 25. As shown the inductive distributor comprises a stator 39 and a rotor which is rotated in synchronism with the helix drum 12. The rotor comprises a single pole 40 carrying a winding 41 to which the signal currents are applied. The substantially semi-circular rotor portion 42 provides a return magnetic circuit between the pole 40 and the poles of the stator 39. The synchronous rotation of the rotor pole 40 induces signal currents in the re-' spective windings 43 on the series of stator poles in predetermined order. Each of the induction windings 43 is connected to one of the series of windings 25 of the electromagnet assembly as shown. One terminal of each winding 25 is connected to a center tap 44 on coil 43 and the rectifiers 45 and 46 are connected in conductors 47 to provide full-wave rectification of the signals impressed on the coils 25. With this arrangement, the pole pieces 25 are progressively energized to effect a travelling-wave actuation of the marking element 15 in exactly the same manner as with the commutator of FIG. 6.

Novel features of the above-described recorder which are not claimed herein, are claimed in the co-pending applications, Ser. Nos. 839,959; 861,528 and 861,529.

While two embodiments of the invention have been described for the purpose of explaining the underlying principles thereof, various modifications of the construction shown and described may be made without departing from the scope of the invention. For example, the number and specific arrangement of the energizing windings 25 may be changed and the number of salient poles of the electromagnetic assembly 20 may be altered in accordance with well known principles of magnetic circuit design. Furthermore, it will be obvious that the mounting and construction of the marking or pressure bar 15 may be considerably altered while retaining the transverse flexibility required to obtain uniform marking Without bodily movement of the entire bar. Also, the

inductive rotor, FIG. 7, may have a second pole opposite present applicant, Ser. No. 839,959 (shown by way of example engaging the pressure-sensitive side of the blank).

I claim: 1. A recorder comprising an elongated marking member in the form of a flexible blade, means to move a pressure-responsive recording blank past the edge of said marking member and means to actuate said marking member into marking relation with said recording blank in response to electric signals, said last-mentioned means comprising a magnetic core assembly provided with spaced poles forming an array substantially co-extensive with said flexible blade, a plurality of distributed overlapping as t windings disposed along the length of said core assembly and means to successively apply signal currents to said windings in predetermined order to thereby move the point of marking pressure across the blank.

2. A recorder according to claim 1 in which said means to successively apply signal currents'to the distributed windings on said core assembly includes commutator segments and contact brushes.

3. A recorder according to claim 1 in which said means to successively apply signal currents to the distributed windings on said core assembly includes a rotary inductive distributor.

4. A recorder comprising an elongated marking memher having a substantially rectilinear marking edge, said member being laterally flexible to permit distortion of said marking edge into curvilinear outline in the plane of said member, means to move a pressure-responsive recording blank past themarking edge of said marking member, the length of said marking member being substantially equal to the width of said recording blank, and electric signal-responsive means to actuate and distort said elongated marking member to apply marking pressure to said recording blank at separate localized areas thereon, said electric signal-responsive means including a gapped magnetic core and an elongated, notched, laterally flexible armature slidably supported on said core adjacent the gap in the core and attached to said elongated marking member along the entire length thereof.

5. A recorder according to claim 4 in which means are provided to support the recording blank beneath the predetermined marking areas, said means having a sharply defined contact area engaging said recording blank at the edge of said marking member which area is synchronized with the movement of the localized-area contact of the marking member with said blank.

6. Arecorder comprising means for feeding a recording blank, contact means engaging one side of said blank with uniform scanning movement across the Width of the blank, marking means including a movable member on the other side of said recording blank, said member having a marking edge for engagement with said blank along a line intersecting the scanning movement of said contact means, and electromagnetic means to apply localized force to the said movable member at the point of engagement of the contact means with said recording blank to mark the same Without bodily shifting theentire movable member as a unit, said electromagnetic means including a series of overlapping coils, a core member with salient poles on which said coils are wound, and means for effecting progressive energization of said overlapping coils in groups along the length of said core member.

7. A recorder comprising. means for feeding a recording blank, contact means engaging said blank to provide marking in successive elemental areas along a scanning line, said contact means including a unitary elongated recording element having a continuous blank-engaging edge, said recording element being formed to permit transverse displacement at localized sections of said edge at which the recording is taking place on the blank with respect to the position of the rest of said recording element, and electro-responsive means comprising an electromagnet assembly to effect localized transverse displacement of said edge Where recording is desired, said electromagnet assembly having a magnetizable core including a linear array of pole pieces and a plurality of overlapping windings, each surrounding more than one of said pole pieces.

8. A recorder according to claim 7, in which commutator means is provided to energize said overlapping windings in predetermined order, said commutator means being synchronized with the scanning movement of said contact means.

9. A recorder comprising means for feeding a recording blank, contact means engaging said blank to provide marking in successive elemental areas along a scanning line, said contact means including a unitary elongated recording element having a continuous blank-engaging edge, said recording element being formed to permit transverse displacement at localized sections of said edge at which the recording is taking place on the blank with respect to the position of the rest of said recording element, and electro-responsive means to effect localized transverse displacement of said edge where recording is desired, said last-mentioned means comprising a rotary inductive distributor having a rotatable inductor element synchronized with a scanning movement of said contact means, and a plurality of stationary coils in mutual inductive relation to said inductor element, said means to effect localized transverse displacement of the edge of said recording element further comprising segmented electromagnetic means connected to the respective coils of said inductive distributor for actuating different sections of said recording element in response to the rotation of said rotatable inductor element.

10. A recorder comprising means for feeding a recording blank of the pressure-sensitive type, a helix-and-bar recording unit for marking said blank in response to applied electrical signals, said recording unit comprising a movable bar having transverse slots and an'edge portion engaging said blank and extending substantially across the width of said blank, and magnetic means for actuating said movable bar including a series of coils forming an array parallel to the surface of said blank and to said edge portion of said movable bar, an elongated magnetizable armature adjacent to and coextensive with the movable bar, and means for progressively energizing said coils in synchronism with the rotation of said helix.

11. A recorder comprising means for feeding a recording blank of the pressure-sensitive type, a helix-and-bar recording unit for marking said blank in response to applied electrical signals, said recording unit comprising an electromagnet assembly including a plurality of core members arranged side-byide across the width of said blank and armature elements for the respective core members, a fiexible member attached to said armature elements and disposed adjacent the surface of the blank to mark said blank in response to movement of the armature elements, and means for progressively energizing the core members in sequence.

12. A recorder according to claim 11, in which overlapping coils are wound on adjacent sets of core members of said electromagnet assembly, each coil surrounding at least three core members.

13. A recorder according to claim 11, in which the means for progressively energizing the core members in sequence comprises a commutator synchronized with the helix of the recording unit.

14. A recorder according to claim 11, in which the means for progressively energizing the core members in sequence comprises rotary inductive means having a series of coils connected respectively to said side-by-side core members.

15. A recorder according to claim 11, in which the flexible marking member consists of a thin fiat blade having a plurality of transverse slots for imparting edgeflexibility to the marking member, said blade slidably supported on said side-by-side core members.

16. A signal-controlled marking mechanism for electric signal recorders and the like, comprising a movable blank-scanning member having an anvil, another member consisting of an elongated recording element in the form of a thin flat magnetizable strip having a straight edge, said strip being substantially rigid longitudinally along said edge but capable of transverse displacement with respect to the rest of the strip at localized points of said edge at which recording is taking place on the blank, the edge of said strip intersecting said anvil to define an elemental blank-scanning spot, said elongated recording element being movable in the horizontal plane 55 form of a thin flat bar of magnetizable material having a continuous edge facing the recording blank and having a multiplicity of transverse slits to render the bar transversely flexible in localized regions of its length.

References Cited in the file of this patent UNITED STATES PATENTS 2,380,467 Ressler July 31, 1945 2,658,106 Hell NOV. 3, 1953 2,680,056 Olden June 1, 1954 2,785,039 Artzt Mar. 12, 1957 

1. A RECORDER COMPRISING AN ELONGATED MARKING MEMBER IN THE FORM OF A FLEXIBLE BLADE, MEANS TO MOVE A PRESSURE-RESPONSIVE RECORDING BLANK PAST THE EDGE OF SAID MARKING MEMBER AND MEANS TO ACTUATE SAID MARKING MEMBER INTO MARKING RELATION WITH SAID RECORDING BLANK IN RESPONSE TO ELECTRIC SIGNALS, SAID LAST-MENTIONED MEANS COMPRISING A MAGNETIC CORE ASSEMBLY PROVIDED WITH SPACED POLES FORMING AN ARRAY SUBSTANTIALLY CO-EXTENSIVE WITH SAID FLEXIBLE BLADE, A PLURALITY OF DISTRIBUTED OVERLAPPING WINDINGS DISPOSED ALONG THE LENGTH OF SAID CORE ASSEMBLY AND MEANS TO SUCCESSIVELY APPLY SIGNAL CURRENTS TO SAID WINDINGS IN PREDETERMINED ORDER TO THEREBY MOVE THE POINT OF MARKING PRESSURE ACROSS THE BLANK. 